fix(worker-client): stop swallowing mutating hub call failures

TryInvokeAsync catches every exception and returns null, which is fine
for read-only calls but hid real HubException reasons behind a generic
"offline" message for the 7 mutating call sites (RestoreDefaultAgents,
UpsertPrimeSchedule, AddDailyNote, CleanupFinishedWorktrees,
ResetAllWorktrees, ForceRemoveWorktree, BuildPlanningIntegrationBranch)
— the same bug class fixed for ApproveReview in e1807fd. Each of the 22
TryInvokeAsync call sites was audited; the 15 read-only ones are left
unchanged (empty/offline is the right display). For the 7 switched to
a direct hub invoke, every caller was checked and, where it had no
catch, one was added so the exception surfaces (StatusMessage,
ShowErrorAsync/CombinedWarning) instead of crashing.

src/ClaudeDo.Ui/ViewModels/Islands/DetailsIslandViewModel.cs

@@ -311,6 +311,7 @@ public sealed partial class DetailsIslandViewModel : ViewModelBase, IDisposable
         Prep = new PrepPanelViewModel(worker);
 
         Notes = new NotesEditorViewModel(_notesApi);
+        Notes.ErrorReported += msg => { if (ShowErrorAsync is not null) _ = ShowErrorAsync(msg); };
         Subtasks.CollectionChanged += (_, _) => NotifyStepsChanged();
         Subtasks.CollectionChanged += (_, _) => Merge.SyncChildOutcomes(HasChildOutcomes, Subtasks.Count);
         Attachments.CollectionChanged += (_, _) => OnPropertyChanged(nameof(FilesBadge));